<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>

    <script src="./lib/vue.min-2.6.11.js"></script>
</head>

<body>

    <div id="app">
        <input type="button" value="浪起来" v-on:click="lang">

        <input type="button" value="别浪" v-on:click="stop">
  
        <h3 v-text="msg"></h3>
    </div>

    <script>
        const vm = new Vue({
            el: '#app',
            data: {
                msg: '猥琐发育，别浪~~~~~~!',
                intervalId: null
            },
            methods: {
                lang: function () {

                    if(this.intervalId != null) return 

                    const that = this 
                 
                    this.intervalId = setInterval(function () {

                        const start = that.msg.substring(0, 1)
                       
                        const end = that.msg.substring(1)
                    
                        that.msg = end + start
                    }, 400)

                },
                stop: function () {
                    clearInterval(this.intervalId) 
                    this.intervalId = null
                }

            }
        })

        console.log(vm);


    </script>

</body>

</html>